Pulmonary Tuberculosis (pulmonary TB) is a chronic infectious disease that is caused by the bacterium Mycobacterium tuberculosis. It is still considered as one of the leading cause of death among other infectious diseases. Chronic infection causes the body in a state of oxidative stress. In a stressful condition, the production of stress hormone increases and it can affect the level of sugar in blood, which it can trigger Diabetes Mellitus to occur. In this study, we present Chi Square Automatic Interaction Detection (CHAID) method to classify categorical data by dividing the data set into subgroups. The goal of this research is to know the factors that are related to the occurrence of type 2 of Diabetes Mellitus (DM) on TB patients. Another purpose is to make a classification using CHAID. In this research, the data obtained from Cipto Mangunkusumo Hospital (RSCM) for 2012 - 2017. Where the dependent variable is type 2 DM status, while the independent variables are gender, age, body mass index, level of neutrophil, level of lymphocytes, erythrocyte sedimentation rate, and anti tuberculosis medicines such as rifampicin, isoniazid, pyrazinamide, ethambutol, and streptomicin. There are seven classes are obtained by classification using CHAID. Where the experimental results are showed by Table I and Table II. The result from analysis of  CHAID method shows that the factors related to the occurrence of type 2 DM on TB patients are age, body mass index, gender and pirazinamid (Z). Based on CHAID method, a classification of the occurrence of type 2 DM on pulmonary TB patients is obtained, which is pulmonary TB patients who are ≥ 40 years old, have body mass index ≥ 25 kg/m², and the most patients are male (Class-4^th).